The present disclosure relates generally to rectifying contacts to an n-type oxide material or a substantially insulating oxide material.
Many electronic devices are based on oxide semiconductors. Such devices may include thin-film transistors with oxide semiconductor channel layers or diodes incorporating oxide semiconductor materials.
The formation of high quality rectifying contacts to oxide semiconductors may, in some instances, be difficult. One method for forming a rectifying contact includes doping a material n-type and p-type in adjacent regions to form a diode. This method may, in some instances, not be suitable, as many oxide semiconductors have a tendency toward either n-type or p-type conductivity, with the opposite conductivity being difficult to attain. Many oxides (e.g., ZnO, In2O3, and SnO2) tend strongly toward n-type, and their electron affinity is relatively large (˜4-5 eV). As such, a p-type material or metal suitable for formation of a rectifying contact should have a relatively large work function and/or suitable interface properties so as to provide a sufficient barrier to charge injection into the n-type layer when the rectifying contact is biased in the negative direction (i.e., with a relative positive potential applied to the n-type layer). Where a rectifying contact may be obtained, complex surface preparation and low-energy deposition processes may be necessary.
As such, it would be desirable to provide a p-type material that is capable of forming a rectifying contact to n-type oxides.